Nest can't resolve dependencies of the RestController

Question

I'm working in a new Nest.js project and whenever I try to start the server:

[ExceptionHandler] Nest can't resolve dependencies of the RestController (?). Please make sure that the argument dependency at index [0] is available in the RestModule context.

I've checked the documentation and looked everywhere and i cannot spot the problem. The RestController class injects UsersService , which is exported by UsersModule and imported in RestModule . Everything looks fine but didn't work.

This is my code:

app.module.ts :

import { Module } from '@nestjs/common'
import { RestModule } from './rest/rest.module'

@Module({
  imports: [
    RestModule
  ]
})
export class AppModule { }

rest.module.ts :

import { Module } from '@nestjs/common'
import { RestController } from './rest.controller'
import { UsersModule } from '../users/users.module'

@Module({
  imports: [
    UsersModule
  ],
  controllers: [
    RestController
  ]
})
export class RestModule { }

rest.controller.ts :

import { Controller, Inject, Get } from '@nestjs/common'
import { UsersService } from '../users/users.service'
import { User } from '../users/user.interface'

@Controller()
export class RestController {

  constructor (
    @Inject()
    private readonly usersService: UsersService
  ) { }

  @Get()
  async getAll (): Promise<User[]> {
    return this.usersService.findAll()
  }

}

users.module.ts :

import { Module } from '@nestjs/common'
import { UsersService } from './users.service'

@Module({
  providers: [
    UsersService
  ],
  exports: [
    UsersService
  ]
})
export class UsersModule { }

users.service.ts :

import { Injectable } from '@nestjs/common'
import { User } from './user.interface'

@Injectable()
export class UsersService {

  async findAll (): Promise<User[]> {
    return new Promise((resolve, reject) => resolve([]))
  }

}

Thank you in advance!

Answer 1

In your RestController class you have to remove the @Inject() from your constructor:

constructor (
  private readonly usersService: UsersService
) { }

@Inject() can be used for non-class-based provider tokens .